This study is to determine the safety, maximum tolerated dose, and preliminary evidence of the efficacy of rHuKGF as measured by incidence, duration, and severity of oral mucositis and diarrhea when administered to colorectal carcinoma patients scheduled to receive chemotherapy with 5-FU and leucovorin. 5-FU/leucovorin chemotherapy can cause stomatitis and severe diarrhea; animal studies have shown that rHuKGF, a substance similar to the protein keratinocyte growth factor, may delay or decrease the diarrhea and stomatitis. The drug or a placebo will be given to subjects for 3 days before they begin chemotherapy.